1. Field of the Invention
The present invention relates to a can seamer available in a can filling line, and more particularly, to a can seamer provided with means for facilitating replacement of seaming rolls, a seaming chuck and a knockout pad required as a result of change of a can size or the like.
2. Description of the Prior Art
At first, a construction and an operation of a conventional can seamer in the prior art will be described with reference to FIGS. 1 to 14. FIGS. 11 to 13 illustrate a structure of a seaming chuck and seaming rolls in a can seamer in the prior art, FIG. 11 is a plan view of a seaming mechanism in a conventional rotary seamer, FIG. 12 is a side view of seaming rolls, and FIG. 13 is a vertical cross-section view of a seaming mechanism. In these figures, reference numeral 11 designates a first seaming roll, numeral 12 designates a second seaming roll, and numeral 13 designates a seaming chuck. In addition, reference numeral 14 designates a seaming lever, which is inserted around a seaming roll shaft 15 via splines (serrations) 15a, which can be extracted downwards, but which is fixed to the same shaft 15 so as to be integrally rotatable, and to the same lever 14 is fixed a shaft 16. Each of the seaming rolls 11 and 12 is rotatably suspended at the center of the same shaft 16 via a bearing 18 fixed to the shaft 16 by means of a screw 17. On the other hand, the seaming chuck 13 is mounted via splines (or serrations) 22 to the bottom end of a rotary cylinder 21 which is rotatably supported from a rotary frame 19 via a bearing 20, so that the seaming chuck 13 can rotate integrally with the same rotary cylinder 21. Also, within the rotary cylinder 21, a knock-out rod 23 penetrates so as to be slidable in the vertical direction. Reference numeral 27 designates a connecting bracket,.which integrally connects the seaming lever 14 and the seaming chuck 13. More particularly, the same bracket 27 is connected with the seaming chuck 13 via flanges 28 provided along its outer circumference, and is connected with the seaming lever 14 via a ring 29, and this ring 29 is rotatably fixed by means of a lock nut 30 engaged with the connecting bracket 27. In addition, reference numeral 31 designates a bolt for positioning the seaming chuck 13 in the vertical direction with respect to the rotary cylinder 21.
At the time of seaming a can, normally the can exerts upon the seaming chuck 13 a push-up force, and the seaming rolls 11 and 12 are also exerted a reaction force generated upon pushing a can lid during the operation of seaming a can, and are pushed upwards. In addition, in order to prevent the seaming lever 14 from slipping out of the seaming roll shaft 15, a cam 35 rotatable about a shaft 37 mounted to the seaming lever 14, is provided, and by rotating a lever 36, the cam 35 is made to enter a notch groove provided on the seaming roll shaft 15 to serve as a stopper.
On the other hand, the top end of the seaming chuck 13 butts against a flange of the rotary cylinder 21, and this rotary cylinder 21 is rigidly supported in the vertical direction with respect to a seamer main body via a bearing 20. Furthermore, with regard to the structure of the seaming roll shaft 15, for the sake of convenience, description will be made with reference to FIG. 1. Since the seaming roll shaft 15 is pushed upwards by means of a compression spring 43 via a cam lever 39, when the seaming lever 14 supporting the seaming rolls 11 and 12 is fixed to the seaming roll shaft 15, its top end butts against a washer 38 mounted to the rotary frame 19 (shown at E). Also, between the cam lever 39 and the rotary frame 19 is formed a gap space F.
By means of the above-mentioned arrangement, vertical positions of the seaming chuck 13 and the seaming rolls 11 and 12 can be insured. It is to be noted that in FIG. 1, reference numeral 41 designates a cam follower, numeral 42 designates a seamer main body frame, numeral 42a designates a cam groove, and when a can seaming mechanism rotates, as a result of the action of the cam groove 42a and the cam follower 41, the seaming roll shaft 15 rotates, hence the seaming lever 14 swings, and the seaming rolls 11 and 12 alternately perform seaming operations.
Next, description will be made on operations for changing a type of cans. When it is necessitated to replace the seaming rolls 11 and 12 and the seaming chuck 13 in response to change of a can lid diameter, under the condition where a can is not present, the can seamer is rotated to move the seaming rolls up to a position where working is easy, the top end of the seaming roll shaft 15 is depressed by means of a tool, and after a gap space has been formed between the seaming lever 14 and the washer 38, the bolt 31 is loosened. Simultaneously therewith, the cam 35 is disengaged from the notch groove in the seaming roll shaft 15 by turning the lever 36, and the seaming rolls 11 and 12 and the seaming chuck 13 are pulled down as gripped by hands. Then, since the seaming lever 14 and the seaming chuck 13 are integrally connected by the connecting bracket 27, the seaming lever 14 is disengaged from the seaming roll shaft 15 via the splines 15a, also the seaming chuck 13 is disengaged from the rotary cylinder 21 via the splines 22, and they are integrally pulled down via the connecting bracket 27.
Subsequently, when it is intended to mount a seaming lever having seaming rolls of changed sizes assembled and a seaming chuck of changed sizes, since the spline diameters are identical to those of the used ones, after the splines of the seaming lever 14 were aligned with the splines 15a of the seaming roll shaft 15, the splines of the seaming chuck 13 were aligned with the splines 22 of the rotary cylinder 21, and they were pushed in, the seaming chuck 13 is fixed by fastening the bolt 31, the seaming lever 14 is fixed to the seaming roll shaft 15 by turning the lever 36 to insert the cam 35 into the notch groove in the seaming roll shaft 15, and if a depressing force is removed from the top end of the same shaft 15, the mounting work is finished.
Another example of a can seamer in the prior art is seen in Laid-Open Japanese Utility Model Specification No 54-9137 (1979), and in the following, this will be explained with reference to FIG. 14. In this figure, reference numeral 101 designates seaming rolls, which are rotatably mounted respectively around shafts 103 and 104 fixed to a seaming lever 102. Reference numeral 105 designates a seaming chuck, which is threadedly fixed to a bottom end of a rotary cylinder 106, and a knock-out pad 109 is fixed by a screw 108 to the bottom end of a knock-out rod 107 which penetrates through the same rotary cylinder 106 in a vertically slidable manner. This knock-out pad 109 is projectable from a recessed portion 110 at the bottom of the above-mentioned chuck 105. In addition, the upper portion of the above-mentioned knock-out rod 107 is inserted via a ball bearing into a knock-out carrier 112, the same knock-out carrier 112 is guided by a knockout carrier guide 111, and is prevented from rotating by means of an anti-rotation guide pin not shown which is parallel to a center axis of the knock-out rod 107. Also, to the knock-out carrier 112 is mounted a cam follower 113, and provision is made such that when the can seamer is operated the cam follower 113 may move up and down following a profile of a groove cam 114 and the movement may be transmitted via the ball bearing to the knock-out rod 107. Parallel twin faces for engaging with a spanner are machined on a shaft 107a at the top of the same knockout rod 107.
In order to remove the knock-out pad 109 from the knock-out rod 107 for the purpose of changing the type of the knock-out pad as a result of change of can sizes, while the top shaft 107a of the knock-out rod 107 is held by means of a spanner, the screw 108 is loosened, and thereby the knock-out pad 109 is removed. When a knock-out pad to be replaced is mounted, it is only necessary to perform the above-mentioned steps of operation in the reverse sequence.
As will be seen from the above description, the type-changing work at the time of changing can sizes in the can seamer in the prior art as shown in FIGS. 11 to 13 had a shortcoming that it necessitated a lot of time and labor because of the fact that a manually operated handle was used for rotating a seaming mechanism and at the time of replacement of seaming rolls also the top end of a seaming roll shaft had to be held by means of a hand tool.
In addition, mounting of a seaming lever and positioning in the vertical direction in the heretofore known can seamer as shown in FIGS. 11 to 13 relied upon the method of aligning a horizontal notch groove cut in a seaming roll shaft with a cam 35 provided on a seaming lever and fixing them by inserting the cam plate into the notch groove, and with such structure, it necessitates a lot of time to adjust a clearance in the vertical direction of the seaming roll shaft when can sizes are changed. Explaining the reasons, a seaming chuck is spinning at a high speed and also is making rotary movement at a high speed along a circumference as accompanied by seaming rolls, and so, if the clearance in the vertical direction of the seaming roll shaft should deviate from a predetermined tolerable value, baking would arise or unacceptable seaming caused by vibration would occur. Therefore, in a seaming process between a can and a can lid, the seaming chuck pressing the can lid and the seaming roll for carrying out seaming would necessitate a high precision in positioning. However, in the seaming lever mounting structure in the prior art, clearance adjustment involved problems such as requiring a lot of labor and time because each time the seaming lever must be extracted from the seaming roll shaft to replace or grind a shim.
Also, in the heretofore known apparatus shown in FIG. 14, since seaming chucks mountable to a single seamer are many, if it is intended to replace a knock-out pad, each time the top end 107a of a knock-out rod must be restrained by means of a spanner and the knock-out pad 109 must be disengaged by releasing the screw 108, and so, there was a problem that a lot of labor and time were necessitated for mounting and dismounting of the same pad.
It is therefore one object of the present invention to provide a can seamer, in which at the time of replacement of a seaming roll, positioning of a seaming roll shaft can be achieved automatically, and hence an efficiency of a replacement work for a seaming roll can be improved.
Another object of the present invention is to provide a can seamer, in which vertical alignment of a seaming lever and a seaming roll shaft for fitting can be adjusted in a simple manner.
Still another object of the present invention is to provide a can seamer, in which replacement of a knock-out pad can be done in one-touch operation.
According to one feature of the present invention, there is provided a type-changing apparatus in a can seamer, in which a plurality of can seaming mechanisms are disposed at an equal pitch along a circumference that is equidistant from a vertical center axis, the same can seaming mechanism is provided with a can table for pushing up a bottom of a can while it is rotating, a seaming chuck for supporting a can lid from the above while rotating at the same speed in the same direction as the aforementioned can table, and a set of two seaming rolls swinging about a seaming roll shaft separate from the above-mentioned seaming chuck, and provision is made such that during the period when a can covered with a can lid fed at a proper timing by means of a conveyor is being transported along a circumference that is equidistant from the center axis while rotating about a vertical axis as gripped between the aforementioned can table and the above-described seaming chuck, the top edge of the can and the can lid are seamed by the aforementioned seaming roll and then carried out to the next step of process; improved in that the above-described type-changing apparatus comprises a control mechanism which can arbitrarily drive the same can seaming mechanisms one pitch by one pitch after it has detected a rotational angle of the seaming roll shaft and has stopped the can seaming mechanism at a predetermined position by controlling a drive motor, and an actuator mounted on a can seamer main body frame and capable of depressing the top end of the aforementioned seaming roll shaft at one of the can seaming mechanism stop positions.
According to another feature of the present invention, there is provided the above-featured type-changing apparatus in a can seamer, wherein a rotational angle detector for the seaming roll shaft consists of a disc rotating as interlocked with rotation of the seaming roll shaft, and an approach sensor for detecting a rotational angle of the same disc.
According to still another feature of the present invention, there is provided the first-featured type-changing apparatus in a can seamer, wherein a rotational angle detector for the seaming roll shaft is a fixed position sensor for detecting the top end of the seaming roll shaft.
According to a further feature of the present invention, there is provided a seaming roll mounting/dismounting mechanism in a can seamer, in which a plurality of can seaming mechanisms are disposed at an equal pitch along a circumference that is equidistant from a vertical center axis, the same can seaming mechanism is provided with a can table for pushing up a bottom of a can while it is rotating, a seaming chuck for supporting a can lid from the above while rotating at the same speed in the same direction as the aforementioned can table, and a set of two seaming rolls swinging about a seaming roll shaft separate from the above-mentioned seaming chuck, and provision is made such that during the period when a can covered with a can lid fed at a proper timing by means of a conveyor, is being transported along a circumference that is equidistant from the center axis while rotating about a vertical axis as gripped between the aforementioned can table and the above-described seaming chuck, the top edge of the can and the can lid are seamed by the aforementioned seaming roll and then carried out to the next step of process; improved in that the same mounting/dismounting mechanism comprises a seaming roll shaft having a tapered bore drilled towards a center axis of the shaft on a vertical plane portion formed at the lower portion of the shaft, a seaming lever holding the seaming rolls and externally fitting around the lower portion of the aforementioned shaft, a set shaft threadedly engaged with a threaded hole formed in the same lever, a cylindrical adjusting screw provided within a cylindrical space of the same set shaft, and a center pin penetrating through a cylindrical inner space of the same adjusting screw and constructed so as to be freely inserted and extracted, so that the vertical positioning of fitting between the seaming lever and the seaming roll shaft can be adjusted by a degree of fitting of the same center pin into the tapered bore.
According to a still further feature of the present invention, there is provided a knock-out pad mounting/dismounting mechanism in a can seamer, which includes a plurality of seaming mechanisms making rotational movement along a horizontal circumference and which performs seaming while making rotational movement; improved in that the aforementioned can seamer includes a knock-out rod, a knock-out pad that is detachably mounted to the same knock-out rod, and a braking mechanism for stopping rotation of the knock-out rod, at the bottom end of the same knock-out rod are formed an anti-rotational protrusion for the knock-out pad, a bore for inserting a headed shaft provided in the knock-out pad, and a step portion capable of supporting a pin provided on the headed shaft, on the other hand, in the knock-out pad are formed a headed shaft mounted in a vertically slidable manner, and a grooved portion for engaging with the pin mounted to the same headed shaft and the above-mentioned protrusion of the knock-out rod, so that by inserting the headed shaft of the above-mentioned knock-out pad into the bore of the knock-out rod and rotating the same shaft, the pin mounted to the same shaft is supported by the step portion formed in the knock-out rod, and the both members can be assembled.
In the can seamer according to the above-mentioned first feature of the present invention, at the time of type-changing work upon can size change, as a measure for rotating the seaming mechanisms, when the respective can seaming mechanisms have come to predetermined positions on the frame of the can seamer main body, a drive motor for the can seamer is stopped and thereby the seaming mechanisms are stopped by means of a control apparatus formed by combining a detector for detecting a rotational angular position of a rotary center axis (vertical axis), the drive motor of the can seamer and a manually operated switch for the same motor. Thereafter, if the above-mentioned manually operated switch is pressed, the seaming mechanisms would move by a distance corresponding to one pitch, and would stop again. In addition, at the predetermined positions on the frame of the aforementioned can seamer main body are mounted actuators, which would act to press the top end of the seaming roll shaft of the stopped seaming mechanisms and thereby facilitate the replacement work of the seaming rolls.
In the can seamer according to the above-mentioned fourth feature of the present invention, at the bottom portion of the seaming roll shaft is formed a plane portion by grinding flat a several teeth of splines (serrations) around which the seaming lever is externally fitted, and also a tapered bore is drilled at right angles to this plane. On the other hand, a threaded hole is formed in the seaming lever, and a set shaft containing therein a center pin having an adjustable projection length and having its tip end tapered similarly to the above-mentioned tapered bore, is threadedly engaged with the threaded hole. After the seaming lever has been fitted to the splines at the bottom of the seaming roll shaft, if this set shaft is screwed in to press the plane portion of the above-mentioned seaming roll shaft, when the seaming lever can be fixed to the seaming roll shaft. In addition, as the diameter of the center pin is made smaller than the inner diameter of the tapered bore, if the center pin is inserted or extracted with the taper on the underside of the center pin aligned with the underside of the tapered bore, the vertical position of fitting between the seaming lever and the seaming roll shaft can be adjusted. In other words, the clearances above and under the seaming roll shaft can be adjusted by positional adjustment of this seaming lever. Also, since the center pin is pressed by a compression spring contained in the center pin projection length adjusting screw within the above-mentioned set shaft, the seaming lever can be dismounted in a simple manner by extracting the center pin from the tapered bore in the seaming roll shaft by externally pulling the center pin.
In the can seamer according to the above-mentioned fifth feature of the present invention, a stepped through-hole is drilled in the shaft portion of the knock-out pad, a short cylindrical portion for centering and a horizontal groove for preventing rotation are provided at the top of the same shaft portion, a compression spring is inserted in the stepped through-hole, a headed shaft machined with a minus groove or a cross groove for engaging with a driver is pushed into the stepped through-hole of the knock-out pad so as to place the same compression spring therebetween to be biased by the compression spring, and a pin is inserted into a lateral hole in the projected headed shaft to retain the same. At the bottom of the knock-out rod is drilled a cylindrical bore concentric with the same rod, a ring-shaped groove is formed at a deep portion of the same bore, two vertical grooves are machined symmetrically in parallel to the center line of the bore from the entrance of the cylindrical bore up to the ring-shaped groove, on the lower surface of the ring-shaped groove is formed a semicircular groove at a position at right angles to the positions of the aforementioned vertical grooves, and at the bottom surface of the knock-out rod are formed a step for centering with the knock-out pad and an anti-rotational horizontal protrusion. The top end of the shaft of the knock-out pad is joined with the bottom end of the knock-out rod, the headed shaft contained in the knock-out pad is pushed into the knock-out rod so that the pin mounted at the tip of the same shaft may be guided along the vertical grooves of the knock-out rod, and when the above-mentioned pin has reached the ring-shaped groove in the knock-out rod, if the headed shaft is rotated by 90.degree. and the headed shaft is released at the position where the pin has aligned with the semi-circular groove of the ring-shaped groove, then mounting of the knock-out pad is finished.
In order to prevent the knock-out rod from rotating at the time of replacement of the knock-out pad, a disc is mounted to the top of the knock-out rod, an actuator such as a pneumatic actuator or the like acting downwards is mounted to the frame of the seamer main body at an appropriate position on the circumference depicted by a point on an upper extension of the center axis of the knock-out rod, and a braking pad is mounted to the tip end of the action rod of the actuator. Upon replacement of a knock-out pad, the seamer is operated in such manner that a turret having the seaming mechanisms mounted thereon may be rotated one pitch by one pitch and knock-out rods may successively come right under the actuator and then may stop, and when the seamer has stopped, the actuator is operated to press the disc at the top of the knock-out rod with the pad mounted at the tip of the action rod to brake the disc, and the knock-out pad is removed by turning the headed shaft from the underside of the knock-out pad by means of a driver. Subsequently, while the knock-out rod is kept braked by the actuator, a new knock-out pad to be replaced is inserted into the knock-out rod and turned, and thereby replacement is completed.
According to the first to third aspects of the present invention, in a type-changing work of a can seamer, since a seaming roll shaft can be automatically constrained by means of an actuator, remarkable advantages that as compared to the can seamer in the prior art in which the seamer was rotated by a manually operated handle and the seaming roll shaft was constrained by means of a hand tool, labor and time can be greatly reduced, are obtained.
According to the fourth aspect of the present invention, in a type-changing work of a can seamer, since setting of a gap clearance in the vertical direction of a seaming roll shaft can be achieved easily by merely adjusting a fitting condition between a tapered bore formed in a seaming roll shaft and a center pin provided in a seaming lever even in the case where dimensions are varied delicately due to temperature variations, remarkable advantages that labor and time necessitated for adjustment of the gap clearance can be saved, are obtained.
According to the fifth aspect of the present invention, since replacement of a knock-out pad accompanying change of can sizes can be carried out by a one-touch operation in a can seamer, remarkable advantages that it is possible to spare labor and time even in a multiple can seamer.
The above-mentioned and other objects, features and advantages of the present invention will become more apparent by reference to the following description of preferred embodiments of the invention taken in conjunction with the accompanying drawings.